using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
using System.Threading;

namespace ProtoTypeShooter
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class Game1 : Microsoft.Xna.Framework.Game
    {
        GraphicsDeviceManager graphics;
        SpriteBatch spriteBatch;

        Texture2D ship,bullet;

        Vector2 spritePosition = new Vector2(200, 300),spriteVelocity;
        KeyboardState keyboardState;
        List<Enemy> enemies = new List<Enemy>();
        List<MyBullet> bullets = new List<MyBullet>();
        double timeElapsed;


        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }

        public void updateBullets()
        {
            foreach (MyBullet bullet in bullets)
            {
                bullet.position += bullet.velocity;
                if (Vector2.Distance(bullet.position, spritePosition) > 500)
                    bullet.isVisible = false;
            }
            for (int i = 0; i < bullets.Count; i++)
            {
                if (!bullets[i].isVisible)
                {
                    bullets.RemoveAt(i);
                    i--;
                }
            }
        }

        public void updateEnemies(GameTime gameTime)
        {

            foreach (MyBullet bullet in bullets)
            {
                foreach (Enemy enemy in enemies)
                {
                    if (Math.Abs(bullet.position.X - enemy.position.X) < 25 && Math.Abs(bullet.position.Y - enemy.position.Y) < 20)
                        {
                            bullet.isVisible = false;
                            enemy.setTexture(Content.Load<Texture2D>("enemyGoBoom"));
                            enemy.die(gameTime);
                        }
                }
            }

            for (int i = 0; i < enemies.Count ;i++ )
            {
                if (enemies[i].timeDead > 0 && gameTime.TotalGameTime.TotalMilliseconds - enemies[i].timeDead > 100)
                    enemies.Remove(enemies[i]);
            }
        }

        public void shoot(GameTime gameTime)
        {
            MyBullet newBullet = new MyBullet(Content.Load<Texture2D>("bullet"));
            newBullet.velocity = new Vector2(0,-1) *5f;
            newBullet.position = spritePosition + newBullet.velocity * 5;
            newBullet.isVisible = true;

            if (bullets.Count < 50)
            {
                if (gameTime.TotalGameTime.TotalMilliseconds - timeElapsed > 400)
                {
                    bullets.Add(newBullet);
                    timeElapsed = gameTime.TotalGameTime.TotalMilliseconds;
                }               
            }
           
        }
        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            // TODO: Add your initialization logic here

            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

            ship = Content.Load<Texture2D>("picsa1");
            bullet = Content.Load<Texture2D>("bullet");
            for(int i=1; i<6; i++)
            {
                enemies.Add(new Enemy(Content.Load<Texture2D>("enemy"), new Vector2(90 * (i), 50)));
            }


            // TODO: use this.Content to load your game content here
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// all content.
        /// </summary>
        protected override void UnloadContent()
        {
            // TODO: Unload any non ContentManager content here
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();

            keyboardState = Keyboard.GetState();


            spritePosition = spriteVelocity + spritePosition;
            if (keyboardState.IsKeyDown(Keys.Up))
                spriteVelocity.Y =- 2;
            else if (keyboardState.IsKeyDown(Keys.Down))
                spriteVelocity.Y = 2;
            else if (keyboardState.IsKeyDown(Keys.Left))
                spriteVelocity.X =- 2;
            else if (keyboardState.IsKeyDown(Keys.Right))
                spriteVelocity.X = 2;
            else
            {
                spriteVelocity.X = 0;
                spriteVelocity.Y = 0;
            }

            if (keyboardState.IsKeyDown(Keys.Space))
                shoot(gameTime);

            updateEnemies(gameTime);
            updateBullets();
            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);

            spriteBatch.Begin();

            foreach (MyBullet bullet in bullets)
            {
                bullet.Draw(spriteBatch);
            }

            foreach (Enemy enemy in enemies)
            {
                enemy.draw(spriteBatch);
            }
            spriteBatch.Draw(ship, spritePosition, Color.White);
            spriteBatch.End();

            base.Draw(gameTime);
        }
    }
}
